Error can not call getNString () when capturing BD values

I am developing a small application of a private clinic and to enter the application, I first select the patient's identifier through JComboBox .

Then, I have a method to fill a arrayList with the patients' data to later fill in a form with said data.

The problem I have when filling this array , before filling it I capture all the values of resultset and in the exception I miss this error:

  

can not call getNString () when field's charset isn't UTF-8

I sense that this exception is jumping because some field of BD has a charset different, but I can not find out why.

I am enclosing my current source where the error is occurring:

public void llenarArrayList() throws UnsupportedEncodingException{
    resultSet = mysql.ejecutaConsulta("SELECT * FROM paciente WHERE NUS =" + jcNuss.getSelectedItem());
    int nuss = 0;
    String cadena = "";
    String primerApellido = new String(cadena.getBytes(), "UTF-8");
    String segundoApellido = new String(cadena.getBytes(), "UTF-8");
    String nombre = new String(cadena.getBytes(), "UTF-8");
    int telf = 0;
    Date fechaNacimiento = null;
    Date fechaAlta = null;
    int medicamento = 0;
    try {
        while(resultSet.next()){
            nuss = resultSet.getInt(1);
            nombre = resultSet.getString(2);
            primerApellido = resultSet.getString(3);
            segundoApellido = resultSet.getNString(4);
            telf = resultSet.getInt(5);
            fechaNacimiento = resultSet.getDate(5);
            fechaAlta = resultSet.getDate(6);
            medicamento = resultSet.getInt(7);  
        }

        System.out.println("nus: " + nuss + " Nombre: " + nombre + " apellido: " + primerApellido + " apellido2: " + 
                    segundoApellido + " telf: " + telf + " fechaNacimiento: " + fechaNacimiento + " fechaAlta: " + fechaAlta+
                    " medicam " + medicamento);

    } catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, ex.getMessage());
    }

thanks in advance.